Dr.Jeff
True Classic
Not sure what's readily available, but if there are the same type universal urethane "hat" bushings available with the same OD as the dogbone ID (not at the lip, but at the main cylinder body). Then you might cut a small groove in the bushings for the dogbone "lip" to fit into (next to the outer edge of the bush). Urethane is forgiving enough to squeeze past the lip until it seats into that new groove. Pretty much the same final outcome but precludes making the sleeve to resize the dogbone bore. And the lip in the groove will secure it in place.